June 29, 2017 Credit: University of Central Florida

Scientists pursue research through observation, experimentation and modeling. They strive for all of these pieces to fit together, but sometimes finding the unexpected is even more exciting.

That's what happened to University of Central Florida's astrophysicist Gal Sarid, who studies comets, asteroids and planetary formation and earlier this year was part of a team that published a study focused on the comet 174P/Echeclus. It didn't behave the way the team was expecting.

"This is another clue that Echeclus is a bizarre solar system object," said University of South Florida physics research Professor Maria Womack, who leads the team.

Comets streak across the sky and as they get closer to the sun look like bright fuzz balls with extended luminous trails in their wake. However, comets are actually bulky spheres of mixed ice and rock, many of them also rich in other frozen volatile compounds, such as carbon monoxide, carbon dioxide, hydrogen cyanide and methanol.

Comets heat up as they get closer to the sun, losing their icy layers by sublimation and producing emission jets of water vapor, other gases and dust expelled from the comet nucleus, Sarid said. Once they move away from the sun, they cool off again. But some comets start showing emission activity while still very far from the sun, where heating is low.

That's what Sarid and Womack research as they study these kinds of distantly active comets. Womack and graduate student Kacper Wierzchos used the Arizona Radio Observatory Submillimeter telescope to observe Echeclus last year as it approached the sun. This work will be part of Wierzchos' doctoral dissertation in applied physics at USF. Sarid provided theoretical expertise for interpreting the observational results.

Echeclus is part of the population of objects called centaurs, which have orbits around the sun at distances between that of Jupiter and Neptune. It is also part of a special group within the centaurs, which sometimes exhibit comet-like activity. Previous research indicated that Echeclus might have been spewing carbon monoxide as its icy material changed phases.

The team found that the levels of carbon monoxide were nearly 40 times lower than typically expected from other comets at similar distances from the sun. This suggests that Echeclus and similar active Centaurs may be more fragile than other comets. Echeclus may have gone through a different physical process from most comets that caused it to lose a lot of its original carbon monoxide, or it may have had less of that substance to begin with.

Understanding the composition of comets and how they work will help researchers understand how our solar system was formed. It will also aid space explorers plan for their travels things to avoid and perhaps hidden resources found within the nucleus of comets that may be useful on deep space missions.

"These are minor bodies that we are studying, but they can provide major insights," Sarid said. "We believe they are rich in organics and could provide important hints of how life originated."

Sarid is determined to solve the puzzle. This week he hosts a group of comet experts at UCF to discuss the mysterious activity of Echeclus and other similar bodies. The idea for the workshop is to capitalize on the local expertise in observation, laboratory and theoretical work that is required to fully understand the mysteries of active comets at great distances from the sun. The inaugural Florida Distant Comets workshop was held a year ago at USF.

"I guess I've always liked challenges," Sarid said from his office at the Florida Space Institute at UCF, where he spends his days trying to decipher the models and mathematical equations related to his work.

Sarid has a Ph.D. in geophysics and planetary Sciences from Tel Aviv University in Israel and completed postdoctoral work at the Institute for Astronomy and the NASA Astrobiology Institute in Hawaii, followed by a second postdoctoral research appointment at Harvard University. He was a part of a team that used the telescopes in Hawaii for several years chasing comets and asteroids for NASA observing campaigns and space missions before joining UCF in 2014.

He teamed up with Womack in 2016 and on this most recent study provided theoretical expertise for interpreting the observational results. The National Science Foundation funds the project, under a grant awarded to USF, with Womack as the principal investigator and Sarid as a co-investigator.

They will continue to look at centaur-type comets and measure the level of their carbon monoxide emission and related activity.

Explore further: NEOWISE identifies greenhouse gases in comets

More information: K. Wierzchos et al. Carbon Monoxide in the Distantly Active Centaur (60558) 174P/Echeclus at 6 au, The Astronomical Journal (2017). DOI: 10.3847/1538-3881/aa689c , https://arxiv.org/abs/1703.07660

M. Womack et al. CO and Other Volatiles in Distantly Active Comets, Publications of the Astronomical Society of the Pacific (2017). DOI: 10.1088/1538-3873/129/973/031001 , https://arxiv.org/abs/1611.00051

After its launch in 2009, NASA's NEOWISE spacecraft observed 163 comets during the WISE/NEOWISE prime mission. This sample from the space telescope represents the largest infrared survey of comets to date. Data from the survey ...

ESA and NASA's Solar and Heliospheric Observatory, or SOHO, saw a bright comet plunge towardthe sun on Aug. 3-4, 2016, at nearly 1.3 million miles per hour. Comets are chunks of ice and dust that orbit the sun, usually ...

(Phys.org)A team of researchers with the Center of Planetary Science (CPS) has finally solved the mystery of the "Wow!" signal from 1977. It was a comet, they report, one that that was unknown at the time of the signal ...

Though not visible to the naked eye or even with binoculars, the green-tailed Comet 45P/Honda-Mrkos-Pajdusakova (HMP) did not escape the gaze of the world-renowned Arecibo Observatory. Scientists from the University of Arizona's ...

A new study has revealed similarities and relationships between certain types of chemicals found on 30 different comets, which vary widely in their overall composition compared to one another. The research is part of ongoing ...

The true identity of centaurs, the small celestial bodies orbiting the sun between Jupiter and Neptune, is one of the enduring mysteries of astrophysics. Are they asteroids or comets? A new study of observations from NASA's ...

Japan has revealed ambitious plans to put an astronaut on the Moon around 2030 in new proposals from the country's space agency.

There are no mechanics on Mars, so the next best thing for NASA's Curiosity rover is careful driving.

Rocky planets are probably a whole lot more common in our galaxy than astronomers previously believedaccording to the latest release of Kepler Space Telescope data last weeka scenario that enhances the prospects for ...

(Phys.org)An international team of astronomers has identified a new extrasolar planet from the data provided by Kepler spacecraft's prolonged mission known as K2. The newly found exoworld, designated EPIC 228735255b, is ...

In our solar system, an asteroid orbits the sun in the opposite direction to the planets. Asteroid 2015 BZ509, also known as Bee-Zed, takes 12 years to make one complete orbit around the sun. This is the same orbital period ...

As NASA's Parker Solar Probe spacecraft begins its first historic encounter with the sun's corona in late 2018flying closer to our star than any other mission in historya revolutionary cooling system will keep its solar ...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Excerpt from:

Bizarro comet challenging researchers - Phys.org - Phys.Org